A sugar compound obtained from a flowering plant called ox knee could protect against bone loss, but more research is needed.

A carbohydrate extracted from a commonly prescribed Chinese medicinal herb could protect against bone loss associated with osteoporosis, a new study finds. As reported in the upcoming December issue of Industrial Crops and Products, researchers demonstrated that a sugar compound called AB90 increases bone mineral density and improves biomechanical properties in a rat model of osteoporosis. Other scientists, however, remain skeptical of the compound’s ultimate therapeutic potential.

“Plant-based therapy including traditional Chinese medicine has become a potential alternative strategy for the management of osteoporosis,” said senior study author Chunyan Yan of Guangdong Pharmaceutical University in China. “Our results provide evidence that daily oral administration of AB90 contributes significantly to the prevention of bone loss and improves the biomechanical quality of bone.”

In the United States today, more than 53 million people either already have osteoporosis or are at high risk due to low bone mass. The disease is marked by reduced bone strength leading to an increased risk of fractures, or broken bones. As the most common type of bone disease, osteoporosis is the major underlying cause of fractures in postmenopausal women and the elderly.

“Osteoporosis is a major health and economic concern, and with the increase in the aging population and the expensive costs of associated healthcare, new and improved therapies are needed not only to treat bone loss, but to prevent it,” said Steven Tommasini, assistant professor of Orthopaedics and Rehabilitation at the Yale School of Medicine in Connecticut, who was not involved in the new study.

Several medications are available for the prevention or treatment of osteoporosis, but their side effects have prompted some researchers to search for natural therapies. In China, the flowering plant Achyranthes bidentata, also known by its English common name, ox knee, is one of the most frequently used medicinal herbs prescribed for the treatment of osteoporosis. The biologically active compounds responsible for the protective effects of A. bidentata extracts have not been clear, but some evidence has suggested that carbohydrates could play a key role.

To explore this possibility, Yan and her team characterized the effects of A. bidentata sugar compounds, or saccharides, in rats that developed osteoporosis after their ovaries had been removed. They found that treatment with a saccharide called AB90 increased the bone mineral content, bone mineral density, and biomechanical quality of the thighbone of these rats, while improving the bone turnover rate.

But Tommasini is skeptical of these results. “I wouldn’t take too much away from this particular study,” he said. “The data are not very convincing as to the beneficial effects of saccharide, especially when compared to the conventional estrogen replacement therapy. There is still a lot of work needed to confirm the authors’ claims before we can begin to think about this as an option for therapy.”

In an attempt to identify the components responsible for AB90’s protective effects, Yan and her team went on to isolate and purify an AB90 fraction called ABW90-1. They found that this novel sugar compound stimulated the differentiation of bone-forming cells called osteoblasts. “The findings suggest that ABW90-1 may be an active component that is responsible for the anti-osteoporotic activities of AB90,” Yan said.

According to Tommasini, more research is needed on the mechanism of the saccharide’s effects before these data can be put to use. “Perhaps there is something there biologically, but these data do not show that,” he said. “If future studies confirm a positive effect on bone mass and we understand how and why this works, then we may see this either developed into a pharmaceutical therapy or used as a supplement in osteoporosis treatment. We are a long way from that point, though.”